spontaneousadj.自发的，自然的，本能的；自然产生的spontaneous boycott自发抵制spontaneous process自发过程spontaneous version[医] 自动倒转spontaneous nucleus自发核spontaneous element自发要素spontaneous routing自发路由Spontaneous edentia自发性无牙spontaneous fission自发裂变spontaneous braking自然制动spontaneous impulse自发冲动